U.S. patent number 9,344,792 [Application Number 13/689,567] was granted by the patent office on 2016-05-17 for ear presence detection in noise cancelling earphones.
This patent grant is currently assigned to Apple Inc.. The grantee listed for this patent is Apple Inc.. Invention is credited to Nicholas A. Rundle.
United States Patent |
9,344,792 |
Rundle |
May 17, 2016 |
Ear presence detection in noise cancelling earphones
Abstract
An electronic device may be coupled to an accessory such as a
pair of earphones. The earphones may have noise cancellation
features that may be implemented using noise cancellation circuitry
in the earphones or in the electronic device. The earphones may
have ear presence sensor structures that determine whether speakers
in the earphones are present at the ears of a user. In one suitable
embodiment, control circuitry in the earphones may be used to
adjust noise cancellation circuitry in the earphones based on
information from the ear presence sensor structures. For example,
the control circuitry may deactivate noise cancellation circuitry
in response to receiving information from the ear presence sensor
structures indicating that the earphones have been removed from a
user's ears. In another suitable embodiment, control circuitry in
the electronic device may adjust noise cancellation circuitry in
the electronic device based on information from the ear presence
sensor structures.
Inventors: |
Rundle; Nicholas A. (San Jose,
CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Apple Inc. |
Cupertino |
CA |
US |
|
|
Assignee: |
Apple Inc. (Cupertino,
CA)
|
Family
ID: |
50773330 |
Appl.
No.: |
13/689,567 |
Filed: |
November 29, 2012 |
Prior Publication Data
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|
Document
Identifier |
Publication Date |
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US 20140146976 A1 |
May 29, 2014 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04R
1/1041 (20130101); H04R 1/1083 (20130101); H04R
2460/01 (20130101) |
Current International
Class: |
G10K
11/16 (20060101); H04R 1/10 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10028169 |
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Jan 1998 |
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JP |
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2011146659 |
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Nov 2011 |
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WO |
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Other References
"Method and System is Disclosed for Modifying Audio Channel Routing
Based on Operational Condition Associated with One or More Audio
Devices." Jul. 16. 2010 (3 pages). cited by applicant .
Acker at al., Smart Audio Output With Presence Sensors: Enabling
Mode Switching Using Head Sets or Ear Buds Synaptics Incorporated,
San Jose, California, Nov. 2, 2005(10 pages). cited by applicant
.
"Automated Play/Pause of Music Based on Aggregated Sensor Data,"
Feb. 2, 2012 (3 pages). cited by applicant .
Free on iPhone: Free Apps, Review for iPhone, "iPhone Proximity
Sensor", posted Jan. 2, 2009, retrieved Sep. 1, 2011. cited by
applicant .
Hisahiro Moriuchi "Universal Earphones: Earphones with Automatic
Side and Shared Use Detection", 2012, 1 page. cited by
applicant.
|
Primary Examiner: Tran; Thang
Attorney, Agent or Firm: Treyz Law Group, P.C. Woodruff;
Kendall P. Hadd; Zachary D.
Claims
What is claimed is:
1. Earphones, comprising: speakers; noise cancellation circuitry;
ear presence sensor structures, wherein the ear presence sensor
structures comprise light-based sensor structures having at least
one light source that emits infrared light and at least one light
detector that detects the infrared light emitted by the at least
one light source; control circuitry configured to gather
information from the ear presence sensor structures indicating
whether the speakers are present at the ears of a user and
configured to adjust the noise cancellation circuitry in response
to the information from the ear presence sensor structures; housing
structures in which the speakers are mounted, wherein at least one
light-based sensor structure is mounted in the housing structures;
and a headband that connects the housing structures, wherein at
least one light-based sensor structure is mounted in the headband,
and wherein the control circuitry adjusts the noise cancellation
circuitry in response to the information from the light-based
sensor structures in the housing structures and the light-based
sensor structures in the headband.
2. The earphones defined in claim 1 further comprising a battery,
wherein the control circuitry is configured to adjust the noise
cancellation circuitry to reduce power consumption of the
battery.
3. A method for operating a pair of earphones having noise
cancellation circuitry and configured to play audio content for a
user comprising: with control circuitry in the earphones, gathering
information from ear presence sensor structures in the earphones on
whether the earphones are present at the ears of the user; and in
response to the information from the ear presence sensor
structures, adjusting the noise cancellation circuitry in the
earphones, wherein the ear presence sensor structures comprise an
accelerometer-based sensor that detects changes in acceleration,
wherein gathering information from the ear presence sensor
structures comprises gathering earphone movement information from
the accelerometer-based sensor, and wherein adjusting the noise
cancellation circuitry comprises deactivating the noise
cancellation circuitry in response to the earphone movement
information indicating that the earphones are in motion.
4. The method defined in claim 3 wherein the information indicates
that the earphones are not present at the ears of the user based on
the detected motion of the earphones and wherein adjusting the
noise cancellation circuitry comprises deactivating the noise
cancellation circuitry in response to determining that the
earphones are not present at the ears of the user.
5. The method defined in claim 4 wherein the audio content is
played through a pair of speakers, the method further comprising:
adjusting the audio content that is played through the speakers in
response to determining that the earphones are not in the ears of
the user.
6. The method defined in claim 5 wherein adjusting the audio
content that is played through the speakers comprises pausing the
audio content that is played through the pair of speakers.
7. The method defined in claim 3 wherein the information indicates
that the earphones are present at the ears of the user and wherein
adjusting the noise cancellation circuitry comprises activating the
noise cancellation circuitry in response to determining that the
earphones are present at the ears of the user.
8. An electronic device operable to receive information from ear
presence sensor structures in earphones coupled to the electronic
device, comprising: noise cancellation circuitry; and control
circuitry configured to gather information from the ear presence
sensor structures indicating whether speakers in the earphones are
present at the ears of a user and configured to adjust the noise
cancellation circuitry in response to the information from the ear
presence sensor structures, wherein adjusting the noise
cancellation circuitry comprises deactivating the noise
cancellation circuitry while continuing to play audio content
through the speakers.
9. The electronic device defined in claim 8 wherein the ear
presence sensor structures comprise an accelerometer-based sensor
and wherein the control circuitry is configured to gather earphone
movement information from the accelerometer-based sensor.
10. The electronic device defined in claim 8 further comprising a
battery, wherein the control circuitry is configured to adjust the
noise cancellation circuitry to reduce power consumption of the
battery.
11. The electronic device defined in claim 8 wherein the control
circuitry is configured to adjust audio playback to the earphones
based on the information from the ear presence sensor
structures.
12. The electronic device defined in claim 8 wherein the control
circuitry is configured to pause audio playback to the earphones
based on information from the ear presence sensor structures
indicating that the speakers in the earphones are not present at
the ears of the user.
13. A method for operating an electronic device having noise
cancellation circuitry and configured to play audio content for a
user through a pair of earphones, comprising: with control
circuitry in the electronic device, gathering information from ear
presence sensor structures in the earphones on whether the
earphones are present at the ears of the user of the electronic
device; and in response to the information from the ear presence
sensor structures, adjusting the noise cancellation circuitry in
the electronic device, wherein the ear presence sensor structures
comprise an accelerometer-based sensor that detects changes in
acceleration, wherein gathering information from the ear presence
sensor structures comprises gathering earphone movement information
from the accelerometer-based sensor, and wherein adjusting the
noise cancellation circuitry comprises deactivating the noise
cancellation circuitry in response to the earphone movement
information indicating that the earphones are in motion.
14. The method defined in claim 13 wherein the information
indicates that the earphones are not present at the ears of the
user based on the detected motion of the earphones and wherein
adjusting the noise cancellation circuitry comprises deactivating
the noise cancellation circuitry in response to determining that
the earphones are not present at the ears of the user.
15. The method defined in claim 14 further comprising: adjusting
the audio content that is played through the earphones in response
to determining that the earphones are not present at the ears of
the user.
16. The method defined in claim 15 wherein adjusting the audio
content that is played through the earphones comprises pausing the
audio content that is played through earphones.
17. The method defined in claim 13 wherein the information
indicates that the earphones are present at the ears of the user
and wherein adjusting the noise cancellation circuitry comprises
activating the noise cancellation circuitry in response to
determining that the earphones are present at the ears of the user.
Description
BACKGROUND
This relates to electronic devices and, more particularly, to
electronic devices with accessories such as earphones.
Accessories such as earphones are often used with media players,
cellular telephones, and other electronic devices. Some accessories
have microphones that are used to form part of a noise cancellation
circuit. When noise cancellation functions are active, the impact
of ambient noise on audio playback can be reduced. Microphones can
also be used to implement voice microphone noise cancellation.
There can be difficulties associated with noise cancelling
earphones. For example, a user who is using earphones to listen to
audio while noise cancellation circuitry in the earphones is active
may occasionally need to remove the earphones. When doing so, the
user may not be able to manually turn off noise cancellation
features. Actively running noise cancellation operations in an
accessory when a user is not using the accessory increases power
consumption and decreases the battery life of the accessory.
It would therefore be desirable to be able to provide improved ways
in which to control operation of an electronic device coupled to an
accessory such as noise cancelling earphones.
SUMMARY
An electronic device may be coupled to an accessory such as a pair
of earphones having noise cancellation features. The noise
cancellation features may be used to reduce the impact of ambient
noise on the audio content that is played through the
earphones.
The earphones may have ear presence sensor structures that
determine whether or not speakers in the earphones are present at
the ears of the user. Information from the ear presence sensor
structures may be used to control the operation of the noise
cancellation features. In one suitable embodiment, noise
cancellation features may be implemented using noise cancellation
circuitry in the earphones. With this type of configuration,
control circuitry in the earphones may adjust the noise
cancellation circuitry in response to information from the ear
presence sensor structures. For example, control circuitry in the
earphones may automatically deactivate noise cancellation circuitry
when information from the ear presence sensor structures indicates
that the earphones have been removed from a user's ears. When
information from the ear presence sensor structures indicates that
the earphones have been placed in or on the user's ears, the
control circuitry in the earphones may, if desired, automatically
activate the noise cancellation circuitry.
In another suitable embodiment, noise cancellation features may be
implemented using noise cancellation circuitry in the electronic
device. With this type of configuration, information from ear
presence sensor structures may be conveyed to control circuitry in
the electronic device. The control circuitry may adjust the noise
cancellation circuitry in response to information received from the
ear presence sensor structures. For example, control circuitry in
the electronic device may automatically deactivate noise
cancellation circuitry when information from the ear presence
sensor structures indicates that the earphones have been removed
from a user's ears. When information from the ear presence sensor
structures indicates that the earphones have been placed in or on
the user's ears, the control circuitry in the earphones may, if
desired, automatically activate the noise cancellation
circuitry.
Controlling the operation of noise cancellation circuitry based on
whether or not the earphones are present at the user's ears may
reduce the power consumption of a battery in the earphones or in
the electronic device.
The ear presence sensor structures may include switch-based
sensors, accelerometer-based sensors, light-based sensors, or other
suitable types of sensors.
Further features of the invention, its nature and various
advantages will be more apparent from the accompanying drawings and
the following detailed description of the preferred
embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front perspective view of an illustrative electronic
device and associated accessory in accordance with an embodiment of
the present invention.
FIG. 2 is a schematic diagram of an illustrative electronic device
and associated accessory in accordance with an embodiment of the
present invention.
FIG. 3 is a schematic diagram of an illustrative electronic device
and associated accessory in which noise cancellation circuitry is
located in the electronic device in accordance with an embodiment
of the present invention.
FIG. 4 is a schematic diagram of an illustrative electronic device
and associated accessory in which noise cancellation circuitry is
located in the accessory in accordance with an embodiment of the
present invention.
FIG. 5 is a perspective view of an illustrative speaker housing
such as an earbud speaker housing that has ear presence sensor
structures in accordance with an embodiment of the present
invention.
FIG. 6 is a perspective view of an illustrative speaker housing
such as an in-ear speaker housing that has ear presence sensor
structures in accordance with an embodiment of the present
invention.
FIG. 7 is a perspective view of illustrative earphones such as
over-the-ear headphones that have ear presence sensor structures in
accordance with an embodiment of the present invention.
FIG. 8 is a cross-sectional side view of an earphone housing of the
type that may be provided with sensor structures for detecting the
presence of an ear or other external object in accordance with an
embodiment of the present invention.
FIG. 9 is a flow chart of illustrative steps involved in using an
electronic device and accessory having noise cancellation features
in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
Electronic device accessories such as earphones may be provided
with noise cancellation features. When noise cancellation features
are activated, the impact of ambient noise on audio content that is
played through the earphones can be reduced. Noise cancellation
features may also be used to perform voice microphone noise
cancellation.
Noise cancellation features may be implemented using one or more
noise cancellation microphones. For example, a voice microphone in
the accessory may have an associated noise cancellation microphone
that picks up ambient noise in the vicinity of the voice
microphone.
Earphone speaker housings in an accessory may also have noise
cancellation microphones. For example, each earphone speaker
housing in a headset may have an external noise cancellation
microphone on an outer surface of the earphone speaker housing. In
addition to the external noise cancellation microphone or instead
of the external noise cancellation microphone, each earphone
speaker housing may have an internal noise cancellation microphone
on an interior surface of the earphone speaker housing (e.g.,
adjacent to the ear).
In accessories with more speakers, more noise cancellation
microphones may be used. For example, additional noise cancellation
microphones can be provided in earbuds that contain multiple
drivers or in surround sound accessories. A surround sound
accessory might, for example, have five or six speakers (or more)
and might have a noise cancellation microphone that is adjacent to
each respective speaker.
Accessories such as earphones having noise cancellation features
may be provided with the ability to sense the presence of external
objects. For example, an earphone accessory may be provided with
sensor structures such as ear presence sensor structures that can
determine whether or not the earphones (i.e., the earphone
speakers) are located in or on the ears of a user.
Information gathered by the sensor structures may be used to
control the operation of noise cancellation features in the
earphones. For example, control circuitry in the accessory or in
the electronic device may automatically activate or deactivate
noise cancellation features based on whether or not the earphones
are located in or on the ears of a user. Controlling noise
cancellation features in a pair of earphones coupled to an
electronic device based on whether or not the user is wearing the
earphones may reduce power consumption and extend the battery life
of the earphones and/or of the electronic device.
FIG. 1 is a diagram of a system of the type that may be provided
with an accessory having noise cancellation features for reducing
the impact of ambient noise and sensing structures for detecting
the presence of external objects such as the ears of a user. As
shown in FIG. 1, system 8 may include electronic device 10 and
accessory 20.
Electronic device 10 may include a display such as display 14.
Display 14 may be a touch screen that incorporates a layer of
conductive capacitive touch sensor electrodes or other touch sensor
components or may be a display that is not touch-sensitive. Display
14 may include an array of display pixels formed from liquid
crystal display (LCD) components, an array of electrophoretic
display pixels, an array of plasma display pixels, an array of
organic light-emitting diode display pixels, an array of
electrowetting display pixels, or display pixels based on other
display technologies. Configurations in which display 14 includes
display layers that form liquid crystal display (LCD) pixels may
sometimes be described herein as an example. This is, however,
merely illustrative. Display 14 may include display pixels formed
using any suitable type of display technology.
Display 14 may be protected using a display cover layer such as a
layer of transparent glass or clear plastic. Openings may be formed
in the display cover layer. For example, an opening may be formed
in the display cover layer to accommodate a button such as button
16 and an opening such as opening 18 may be used to form a speaker
port.
Device 10 may have a housing such as housing 12. Housing 12, which
may sometimes be referred to as an enclosure or case, may be formed
of plastic, glass, ceramics, fiber composites, metal (e.g.,
stainless steel, aluminum, etc.), other suitable materials, or a
combination of any two or more of these materials.
Housing 12 may be formed using a unibody configuration in which
some or all of housing 12 is machined or molded as a single
structure or may be formed using multiple structures (e.g., an
internal frame structure, one or more structures that form exterior
housing surfaces, etc.). The periphery of housing 12 may, if
desired, include walls. One or more openings may be formed in
housing 12 to accommodate connector ports, buttons, and other
components. For example, an opening may be formed in the wall of
housing 12 to accommodate audio connector 24 and other connectors
(e.g., digital data port connectors, etc.). Audio connector 24 may
be a female audio connector (sometimes referred to as an audio
jack) that has two pins (contacts), three pins, four pins, or more
than four pins (as examples). Audio connector 24 may mate with male
audio connector 22 (sometimes referred to as an audio plug) in
accessory 20.
Accessory 20 may be a pair of earphones (e.g., earbuds or earphones
with other types of speakers), other audio equipment (e.g., an
audio device with a single earbud unit), or other electronic
equipment that communicates with electronic device 10. The use of a
pair of earphones in system 8 is sometimes described herein as an
example. This is, however, merely illustrative. Accessory 10 may be
implemented using any suitable electronic equipment.
It should be understood that the term "earphones" may refer to any
suitable type of audio headset (e.g., headphones, over-the-ear
headphones, earbuds, earbud-type headphones with ear hooks, in-ear
headphones that extend partially into the ear canal, etc.).
As shown in FIG. 1, accessory 20 may include a communications path
such as cable 26 that is coupled to audio plug 22. Cable 26 may
contain conductive lines (e.g., wires) that are coupled to
respective contacts (pins) in audio connector 22. The conductive
lines of cable 26 may be used to route audio signals from device 10
to speakers in earphone units 28. Earphone units 28 (which may
sometimes be referred to as speakers or earphone housings) may
include sensor structures for determining when earphone units 28
have been placed within the ears of a user. Microphone signals may
be gathered using a microphone mounted in controller unit 30.
Controller unit 30 may also have buttons that receive user input
from a user of system 8. A user may, for example, manually control
the playback of media by pressing button 30A to play media or
increase audio volume, by pressing button 30B to pause or stop
media playback, and by pressing button 30C to reverse media
playback or decrease audio volume (as examples).
The circuitry of controller 30 may communicate with the circuitry
of device 10 using the wires or other conductive paths in cable 26
(e.g., using digital and/or analog communications signals). The
paths in cable 26 may also be coupled to speaker drivers in
earphones 28, so that audio signals from device 10 may be played
through the speakers in earbuds 28. Electronic device 10 may
regulate the volume of sound produced by earbuds 28 by controlling
the audio signal strength used in driving the speakers in earbuds
28.
In one suitable embodiment, sensor signals from sensor structures
in earbuds 28 may be conveyed to device 10 using the conductive
paths of cable 26. With this type of configuration, electronic
device 10 may process the sensor signals and take suitable action
based on a determination of whether or not earphones 20 are located
in or on a user's ears.
A schematic diagram showing illustrative components that may be
used in device 10 and accessory 20 of system 8 is shown in FIG. 2.
As shown in FIG. 2, electronic device 10 may include control
circuitry 32 and input-output circuitry 34. Control circuitry 32
may include storage and processing circuitry that is configured to
execute software that controls the operation of device 10. Control
circuitry 32 may be implemented using one or more integrated
circuits such as microprocessors, application specific integrated
circuits, memory, and other storage and processing circuitry.
Control circuitry 32 may, if desired, include noise cancellation
circuitry and other audio processing circuitry 46.
Input-output circuitry 34 may include components for receiving
input from external equipment and for supplying output. For
example, input-output circuitry 34 may include user interface
components for providing a user of device 10 with output and for
gathering input from a user. As shown in FIG. 2, input-output
circuitry 34 may include communications circuitry 36.
Communications circuitry 36 may include wireless circuitry such as
radio-frequency transceiver circuitry with a radio-frequency
receiver and/or a radio-frequency transmitter. Radio-frequency
transceiver circuitry in the wireless circuitry may be used to
handle wireless signals in communications bands such as the 2.4 GHz
and 5 GHz WiFi.RTM. bands, cellular telephone bands, and other
wireless communications frequencies of interest. Communications
circuitry 36 may also include wired communications circuitry such
as circuitry for communicating with external equipment over serial
and/or parallel digital data paths.
Input-output devices 38 may include buttons such as sliding
switches, push buttons, menu buttons, buttons based on dome
switches, keys on a keypad or keyboard, or other switch-based
structures. Input-output devices 38 may also include status
indicator lights, vibrators, display touch sensors, speakers,
microphones, camera sensors, ambient light sensors, proximity
sensors, and other input-output structures.
Electronic device 10 may be coupled to components in accessory 20
using cables such as cable 26 of accessory 20. Accessory 20 may
include speakers such as a pair of speaker drivers 40 (e.g., a left
speaker and a right speaker). If desired, accessory 20 may include
more than one driver per earbud. For example, each earbud in
accessory 20 may have a tweeter, a midrange driver, and a bass
driver (as an example). Speaker drivers 40 may be mounted in
earbuds or other earphone housings. The use of left and right
earbuds to house respective left and right speaker drivers 40 is
sometimes described herein as an example.
Accessory 20 may include control circuitry such as control
circuitry 45. Control circuitry 45 may, for example, include
storage and processing circuits formed from one or more integrated
circuits or other circuitry. Circuitry 45 in accessory 20 may
include noise cancellation circuitry and other audio processing
circuitry 48, if desired.
Cables such as cable 26 may form a communications path that can be
used in conveying signals between device 10 and accessory 20. The
communications path may be used to transmit audio from circuitry 32
to speaker drivers 40 during playback operations.
The communications path may also be used to convey noise signals.
Noise cancellation may, for example, be performed using the
processing circuitry of device 10 (e.g., using noise cancellation
circuitry 46). In this type of arrangement, noise signals gathered
by one or more microphones in earphones 20 may be routed to
circuitry 46. Circuitry 46 may then route audio signals from which
noise has been cancelled to headset 20. If desired, noise
cancellation operations may be performed locally in headset 20.
With this type of arrangement, noise cancellation circuitry 48 in
headset 20 can receive audio playback signals from device 10 and
can receive noise signals from noise cancellation microphones in
earphones 20. Circuitry 48 can then cancel noise from the played
back audio.
If desired, accessory 20 may include user input devices 42 such as
buttons (see, e.g., the buttons associated with button controller
30 of FIG. 1), touch-based input devices (e.g., touch screens,
touch pads, touch buttons), a microphone to gather voice input,
other microphones such as noise cancellation microphones, and other
user input devices.
To determine whether or not the earbuds in which speaker drivers 40
are located in or on the ears of a user, accessory 20 may be
provided with ear presence sensor structures 44. Ear presence
sensor structures 44 may be configured to detect whether or not the
speakers of earphones 20 are present at the ears of a user. Ear
presence sensors may be formed from force sensors, from switches or
other mechanical sensors, from capacitive sensors, from
resistance-based sensors, from light-based sensors, from
accelerometer-based sensors, and from acoustic-based sensors such
as ultrasonic acoustic-based sensors (as examples). Control
circuitry 45 in accessory 20 and/or control circuitry 32 of
electronic device 10 may use information from ear presence sensor
structures 44 in determining which actions should be automatically
taken by device 10 and/or by accessory 20.
A schematic diagram of device 10 and accessory 20 in a
configuration in which noise cancellation circuitry is located in
device 10 is shown in FIG. 3. As shown in FIG. 3, accessory 20 may
include one or more microphones such as microphones 50. Microphones
50 may include noise cancellation microphones that are used to
gather ambient noise signals associated with speakers 40. For
example, a first microphone 50 may be configured to gather ambient
noise signals associated with a left speaker driver 40, while a
second microphone 50 may be configured to gather ambient noise
signals associated with a right speaker driver 40. Using noise
cancellation techniques, the ambient noise signals can be used to
reduce noise in the audio being played through speakers 40.
Noise cancellation techniques can also be implemented for
microphones. For example, microphones 50 may include a voice
microphone and a corresponding noise cancellation microphone. The
voice microphone may be used to gather a user's voice signals
during telephone calls or to record audio clips, while the
corresponding noise cancellation microphone may be used to gather
ambient noise signals associated with the voice microphone. Ambient
noise signals gathered by the noise cancellation microphone may be
used to reduce noise in the voice signals gathered by the voice
microphone.
Noise cancellation operations may be performed using analog
circuitry or using digital processing techniques. Noise
cancellation operations may be performed locally in accessory 20 or
may be performed remotely in device 10. In the example of FIG. 3,
noise cancellation operations are performed remotely in device
10.
As shown in FIG. 3, device 10 may include audio processing
circuitry 46. Audio processing circuitry 46, which is sometimes
referred to as a codec or audio codec, may be used to generate
audio signals, to receive and process audio signals, and to receive
and process sensor signals from sensor structures 44. Circuitry 46
may include analog-to-digital (A/D) converter circuitry 52 and
digital-to-analog (D/A) converter circuitry 54. Analog-to-digital
converter circuitry 52 in device 10 may be used to digitize analog
signals such as analog audio signals. For example,
analog-to-digital converter circuitry 52 may be used to digitize
one or more analog microphone signals such as analog microphone
signals gathered by microphones 50. Digital-to-analog converter
circuitry 54 may be used to generate analog output signals. For
example, digital-to-analog converter circuitry 54 may receive
digital signals corresponding to the audio portion of a media
playback event, audio for a telephone call, noise signals, an alert
tone or signal (e.g., a beep or ring), or any other digital
information. Based on this digital information, digital-to-analog
converter circuitry 54 may produce corresponding analog signals
(e.g., analog audio).
Audio processing circuitry 46 may be powered by a power source such
as battery 47. If desired, accessory 20 may also include a power
source such as battery 57. This is, however, merely illustrative.
The use of a battery such as battery 57 in accessory 20 is optional
and is only shown as an illustrative example.
Audio processing circuitry 46 may include a digital signal
processor that may be used to perform digital signal processing on
digitized audio signals. For example, if operating accessory 20 in
a noise cancellation mode, noise signals from microphones 50, which
may reflect the amount of ambient noise in the vicinity of speaker
drivers 40 and/or the amount of ambient noise in the vicinity of a
voice microphone) may be conveyed to audio processing circuitry 46
in device 10. Using the processing capabilities of an audio digital
signal processor in circuitry 46, the noise signals can be
digitally removed from digital audio voice signals and from digital
speakers signals.
This is, however, merely illustrative. If desired, circuitry 46 may
perform noise cancellation operations using analog noise
cancellation circuitry. With this type of configuration, noise
signals gathered by microphones 50 may be conveyed to circuitry 46
in device 10. Audio processing circuitry 46 may produce an
anti-noise signal and may convey the anti-noise signal to speaker
drivers 40 along with the audio signal that is to be heard by the
user. The anti-noise signal may be identical to the noise signal
except that it is shifted by 180 degrees with respect to the noise
signal. The anti-noise signal may be superimposed onto the noise
signal such that destructive interference occurs and the two
signals mutually cancel.
Noise cancellation circuitry of the type shown in FIG. 3 may be
controlled manually by the user and/or may be controlled
automatically based on sensor signals gathered by ear presence
sensor structures 44. For example, audio control circuitry 32 may
automatically deactivate noise cancellation functions when
information from sensor structures 44 indicates that earphones 20
have been removed from a user's ears and may automatically activate
noise cancellation functions when information from sensor
structures 44 indicates that earphones 20 have been placed in or on
a user's ears. Because power is required to perform active noise
cancellation operations, automatically controlling noise
cancellation functions based on whether or not earphones 20 are in
a user's ears may optimize the battery life of device 10.
If desired, audio signal processing operations for implementing
noise cancellation functions may be performed locally in accessory
20. As shown in FIG. 4, accessory 20 may include audio signal
processing circuitry 48. Circuitry 48 may include analog-to-digital
converter circuitry 56 (e.g., for digitizing analog audio signals
from a microphone in accessory 20) and digital-to-analog converter
circuitry 58 (e.g., to convert digital signals to analog signals
that are played back through the speakers of accessory 20). If
desired, audio processing circuitry 48 may receive power from a
power supply such as battery 57 or may be powered using other
methods (e.g., device 10 may provide power to accessory 20 via
cable 26 of FIG. 1). The use of a battery such as battery 57 in
accessory 20 is merely illustrative.
Circuitry 48 may be used to locally implement noise cancellation
functions. In a typical local noise cancellation arrangement using
digital processing techniques, analog microphone signals (noise
signals) from microphones 50 are digitized using analog-to-digital
circuitry 56. Processing circuitry 48 may receive audio signals
(e.g., played back music) from device 10 in digital form. Audio
processing circuitry 48 may then use digital processing techniques
to remove noise from the played back audio. The resulting audio
signal may be converted to analog for speakers 40 using
digital-to-analog converter circuitry 58.
This is, however, merely illustrative. If desired, circuitry 48 may
perform noise cancellation operations using analog noise
cancellation circuitry. With this type of configuration, noise
signals gathered by microphones 50 may be conveyed to circuitry 48
in accessory 20. Audio processing circuitry 48 may produce an
anti-noise signal and may convey the anti-noise signal to speaker
drivers 40. The anti-noise signal may be identical to the noise
signal except that it is shifted by 180 degrees with respect to the
noise signal. The anti-noise signal may be superimposed onto the
noise signal such that destructive interference occurs and the two
signals mutually cancel.
Noise cancellation circuitry of the type shown in FIG. 4 may be
controlled manually by the user and/or may be controlled
automatically based on sensor signals gathered by ear presence
sensor structures 44. For example, control circuitry 45 may
automatically deactivate noise cancellation functions when
information from sensor structures 44 indicates that earphones 20
have been removed from a user's ears and may automatically activate
noise cancellation functions when information from sensor
structures 44 indicates that earphones 20 have been placed in or on
a user's ears. Because power is required to perform active noise
cancellation operations, automatically controlling noise
cancellation functions based on whether or not earphones 20 are in
a user's ears may optimize the battery life of earphones 20.
An illustrative earbud speaker housing with an ear presence sensor
is shown in FIG. 5. In the example of FIG. 5, earbud 28 has a
housing such as housing 66 in which one or more speaker drivers
such as speakers 40 of FIG. 2 are mounted.
Conductive structures such as conductive mesh structures 68 and 70
may be mounted in housing 66. As shown in FIG. 5, for example, mesh
structures 68 and 70 may be mounted in the front of housing 66 so
that sound from the speakers inside earbud housing 66 may pass
through the holes of the mesh. If desired, earbud 28 may contain
microphone structures (e.g., when implementing noise cancellation
features in earbud 28). The use of mesh when forming electrode
structures 68 and 70 may allow ambient sound to be picked up by the
noise cancellation microphones in housing 66.
Mesh electrodes 68 and 70 (e.g., metal screen structures) or other
conductive structures in earbud 28 may be used as first and second
terminals in a resistive (resistance-based) sensor. Control
circuitry in housing 66 may be used to apply a voltage across the
first and second terminals while measuring how much current flows
as a result. The control circuitry may use information on the
voltage and current signals that are established between electrodes
68 and 70 to determine whether or not earbud 28 has been placed in
the ear of a user. In the absence of the user's ear, the resistance
between electrodes 68 and 70 will be relatively high. When,
however, earbud 28 has been placed into a user's ear, contact
between electrodes 68 and 70 and the flesh of the ear will give
rise to a lower resistance path between electrodes 68 and 70.
To determine whether or not earbud 28 has been placed within the
user's ear, control circuitry 45 of earbud (and/or control
circuitry 32 of FIG. 2) may measure the resistance between
electrodes 68 and 70 and may compare the measured resistance to a
predetermined threshold. When the measured resistance is below the
predetermined threshold, circuitry 45 can conclude that earbud 28
has been placed in the ear of the user and may, if desired,
automatically activate noise cancellation circuitry. When the
measured resistance exceeds the predetermined threshold, circuitry
45 can conclude that earbud 28 is out of the ear and may, if
desired, automatically deactivate noise cancellation circuitry.
In configurations where noise cancellation functions are performed
remotely in device 10, control circuitry 32 in device 10 may
analyze sensor signals from ear presence sensors in earphones 20
and may automatically activate and deactivate noise cancellation
circuitry in device 10 based on the sensor signals. Configurations
in which noise cancellation is performed and controlled locally in
earphones 20 and in which sensor signals from ear presence sensors
are analyzed by control circuitry 45 in earphones 20 are sometimes
described herein as an example.
In addition to or instead of using mesh 68 and 70 to measure the
resistance of the user's ear, mesh electrodes 68 and 70 may be used
as capacitive sensor electrodes (e.g., to make mutual capacitance
measurements or to make self capacitance measurements). Different
capacitance values may be detected in the presence and absence of
the user's ear in the vicinity of electrodes 68 and 70. This allows
circuitry 45 to use the capacitance measurements to determine
whether or not earbud 28 is in, on, or out of the user's ear.
If desired, earbud 28 may include a sealing member such as
compressible sealing member 72. Sealing member 72 may be used to
form a seal between a user's ear and earbud 28 that helps block
ambient noise while also forming an enclosed cavity adjacent to the
ear canal. In addition to or instead of using mesh 68 and 70 to
detect the presence of a user's ear, an ear presence sensor such as
ear presence sensor 74 may be embedded in or formed on sealing
member 72.
As an example, ear presence sensor 74 may be a switch-based sensor
such as a switch or button that is actuated when a user's ear is
present or absent. Switch 74 may be mounted on an exterior surface
of earbud housing 66 or may be embedded or formed on sealing member
72. Switch 74 may be configured to move inwards (e.g., towards the
interior of housing 66) and to move outwards (e.g., towards the
exterior of housing 66). When earbud 28 is inserted into a user's
ear, switch 74 may be compressed inward. When earbud 28 is out of
the user's ear, switch 74 may move outwards to regain its original
uncompressed state. Circuitry 45 may use information from switch
structures such as switch structure 74 to determine whether or not
earbud 28 has been placed in a user's ear. If desired, a
switch-based ear presence sensor of this type may be implemented
without requiring electrical power.
As additional examples, sensor structure 74 may be an
accelerometer-based sensor, an orientation sensor, or other sensor
that may be used in gathering earphone movement information and/or
determining the location or orientation of earbud 28. Changes in
orientation and/or changes in acceleration may be used to determine
whether or not earphones 20 are in or on a user's ears. For
example, when movement is detected by sensor 74, circuitry 45 can
conclude that earphones 20 are not in the user's ears. When
movement is not detected by sensor 74 for a predetermined period of
time, circuitry 45 can conclude that earphones 20 are not in the
user's ears.
If desired, ear presence sensor 74 may be a pressure or force
sensor configured to measure a pressure or force against sealing
member 72. In force-based sensor schemes, the resistance of a
compressible foam may be measured or a strain gauge output can be
monitored. When force is present, circuitry 45 can conclude that
earphones 20 have been inserted into or mounted on a user's ears,
whereas when force is not present, circuitry 45 can conclude that
earphones 20 are not being worn by the user. Force indicative of a
user's ear pressing against earphones 20 may also be monitored
using piezo-electric force sensors or other force sensors.
These examples are, however, merely illustrative. In general, any
suitable type of sensor may be used to detect the presence and/or
absence of a user's ear in the vicinity of earbud 28.
FIG. 6 is a perspective view of an illustrative in-ear speaker
housing with an ear presence sensor. In the example of FIG. 6,
in-ear earbud 28 includes sealing members 76 configured to extend
partially into the ear canal of a user's ear. Earphones of the type
shown in FIG. 6 are sometimes referred to as ear-canal
headphones.
As shown in FIG. 6, ear presence sensor 74 may be embedded in or
formed on one of sealing members 76. Ear presence sensor 74 may be
an accelerometer-based sensor, a pressure or force sensor, a
capacitive sensor, a switch-based sensor (e.g., sensor 74 may be a
mechanical switch that is actuated when earbud 28 is inserted or
removed from a user's ear), or any other suitable type of sensor
configured to detect the presence and/or absence of a user's ear in
the vicinity of earbud 28.
FIG. 7 is a perspective view of illustrative over-the-ear
headphones having one or more ear presence sensor structures. In
the example of FIG. 7, accessory 20 includes a headband such as
headband 78 with left and right over-the-ear speaker housings 28. A
sealing member such as sealing member 80 may be a ring or layer of
foam or may be any other suitable type of ear pad configured to
form a seal around the user's ear to help block out ambient
noise.
As shown in FIG. 7, accessory 20 may include one or more user
detection sensors such as ear presence sensor structures 82 and 84.
Ear presence sensor structures 84 may be embedded in or formed on
sealing members 80 and may be configured to detect the presence and
absence of a user's ears in the vicinity of speaker housings 28.
Ear presence sensor 82 may be embedded in or formed on headband
portion 78 and may be configured to detect the presence and absence
of a user's head adjacent to headband 78. When information from
sensor 82 indicates that a user's head is not present, device 10
can conclude that the user is not wearing headphones 20. When
information from sensor 82 indicates that a user's head is present,
device 10 can conclude that the user is wearing headphones 20.
Ear presence sensor structures 82 and 84 may be accelerometer-based
sensors, pressure or force sensors, capacitive sensors,
acoustic-based sensors, switch-based sensors (e.g., sensors formed
form mechanical switches that are actuated when a user's ear or
head is present or absent), or any other suitable type of sensor
configured to detect the presence and/or absence of a user's ear or
head.
A cross-sectional side view of an illustrative earbud with a
speaker driver and an associated ear presence sensor is shown in
FIG. 8. As shown in FIG. 8, earbud 28 may have a housing such as
housing 66. Speaker 40 may be mounted within housing 66 overlapping
an acoustic grill formed from structures such as mesh 68 and 70 or
other acoustic mesh. During operation, sound 88 may pass through
the acoustic mesh. For example, speaker 40 may produce sound that
is received by a user's ear or other external object 80.
When external object 80 is sufficiently close to earbud 28, the
presence of external object 80 may be detected. For example,
control circuitry 45 may measure the resistance between mesh
electrodes 68 and 70 using conductive paths 82 or may use
capacitance measurements in monitoring for the presence of object
80. The measured resistance (or capacitance) may then be used to
determine whether earbud 28 is in the user's ear or is out of the
user's ear. Control circuitry 45 may also use sensors such as
sensor 44 of FIG. 8 to monitor for the presence or absence of
external objects such as the user's ear. As shown in FIG. 8, sensor
44 may have a transmitter such as transmitter 44T and may have a
receiver such as receiver 44R. During operation of sensor 44,
sensor 44 may transmit signals such as signal 84 and may gather
reflected signals such as signal 86. The strength of received
signal 86 may be used to measure whether or not external object 80
is in the presence of earbud 28.
Sensor 44 may be a light-based sensor. For example, transmitter 44T
may be a light-emitting diode or laser that emits light 84 (e.g.,
infrared light, visible light, etc.) and receiver 44R may be a
light detector (e.g., a photodiode or phototransistor) that
measures the amount of light 84 that is reflected as reflected
light 86 from external object 80. When the amount of light that is
reflected from external object 80 is high, circuitry 45 can
conclude that earbud 28 is in the user's ear. When the amount of
light that is reflected from external object 80 is low, circuitry
45 can conclude that earbud 28 is out of the user's ear.
If desired, sensor 44 may be a sensor that emits and receives
acoustic signals. For example, transmitter 44T may be an ultrasonic
signal transducer that transmits ultrasonic signals 84. Receiver
44R may be an ultrasonic signal receiver that measures the amount
of corresponding ultrasonic signal 84 that is reflected as
reflected signal 86 from external object 80. When the amount of
ultrasonic signal that is reflected from external object 80 is low,
circuitry 45 can conclude that earbud 28 is not in the user's ear.
When the amount of ultrasonic signal that is reflected from
external object 80 is high, circuitry 45 can conclude that earbud
28 is currently in the user's ear.
In configurations where noise cancellation operations are performed
locally in accessory 20, circuitry 45 in accessory 20 may use
information from sensor structures 44 to control noise cancellation
circuitry 48. For example, when information from sensor structures
44 indicates that earphones 20 have been removed from a user's
ears, control circuitry 45 may automatically deactivate noise
cancellation circuitry 48. When information from sensor structures
44 indicates that earphones 20 have been placed in or on a user's
ears, control circuitry 45 may automatically deactivate noise
cancellation circuitry 48, thereby conserving the battery life of
earphones 20.
In configurations where noise cancellation operations are performed
remotely in device 10, circuitry 32 (FIG. 2) in accessory 20 may
receive information from sensor structures 44 via cable 26.
Circuitry 32 may control noise cancellation functions based on the
information from sensor structures 44. For example, when
information from sensor structures 44 indicates that earphones 20
have been removed from a user's ears, control circuitry 32 may
automatically deactivate noise cancellation circuitry 46. When
information from sensor structures 44 indicates that earphones 20
have been placed in or on a user's ears, control circuitry 32 may
automatically activate noise cancellation circuitry 46, thereby
conserving the battery life of device 10.
A flow chart of illustrative steps involved in using system 8 is
shown in FIG. 9. During the operations of step 100, earphones 20
may be located in or on the ears of a user and may be operated
normally while using sensor circuitry 44 to monitor for the
presence or absence of speaker housings 28 of accessory 20 in or on
the ears of a user. In configurations where earphones 20 are
over-the-ear headphones (FIG. 7), sensor circuitry 44 may be used
to monitor the presence or absence of the user's head near headband
78 or the presence or absence of the user's ears near over-the-ear
speaker housings 28. Circuitry 45 (and/or circuitry 32, if desired)
may be used in evaluating sensor data and taking appropriate
action. Configurations in which control circuitry 45 is used in
taking action based on sensor data are sometimes described herein
as an example.
Examples of operations that may be performed by system 8 during
step 92 include audio-based operations such as playing media
content (e.g., media content stored on device 10 or media content
provided by an online service), providing a user with audio
associated with a telephone call, providing audio associated with a
video chat session to the user, or otherwise presenting audio
content through earphones 20. Audio may be played in stereo so that
left and right earbuds receive corresponding left and right
channels of audio, may be played using a multi-channel surround
sound scheme, or may be played using a monophonic (mono) sound
scheme in which both the left and right channels of audio are
identical. During the audio-based operations of step 92, noise
cancellation circuitry 48 (or noise cancellation circuitry 46 in
device 10) may be active to reduce the impact of ambient noise on
the audio content played through earphones 20. Configurations where
noise cancellation circuitry 48 in earphones 20 is used to perform
noise cancellation operations is sometimes described herein as an
example. It should be understood, however, that the steps of FIG. 9
may also be performed in configurations where noise cancellation
circuitry (e.g., noise cancellation circuitry 46) is located in
device 10.
During the monitoring operation of step 100, circuitry 45 can use
user detection sensors 44 to determine whether or not earphones 20
are in or on the user's ears.
If, during the operations of step 100, it is determined that
earphones 20 have been removed from the user's ears, circuitry 45
may take suitable action at step 102. For example, circuitry 45 may
deactivate noise cancellation circuitry 48 in response to
information from sensor structures 44 indicating that earphones 20
have been removed from the user's ears. If desired, circuitry 32 in
device 10 may adjust the audio content being played based on the
information gathered by sensor structures 44. For example,
circuitry 32 may pause or stop the audio content being played, may
adjust the playback volume (audio signal drive strength), may
switch from a stereo playback scheme to a monophonic playback
scheme, or may take other suitable actions based on information
from sensor structures 44.
After taking suitable actions at step 102, device 10 can be
operated in an earphones-off mode (step 104). For example,
earphones 20 may operate with noise cancellation circuitry
deactivated (i.e., turned off). This may include continuing to play
audio content without performing noise cancellation operations,
operating with paused or stopped audio playback, etc.
During the operations of step 104, ear presence sensor structures
44 may be used to monitor for the presence of earphones 20 in or on
the ears of the user.
If, during the operations of step 104, sensor structures 44
determine that earphones 20 have been placed in or on the user's
ears, appropriate action may be taken at step 106. Suitable actions
that may be taken by system 8 in response to earphones 20 being
placed in or on the user's ears include activating noise
cancellation circuitry 48, resuming media playback, and/or
restoring a previous volume level of the media playback (as
examples). Operations may then proceed to step 100, where system 8
may operate in an earphones-on mode while circuitry 45 monitors
sensor structures 44 to determine when earphones 20 are removed
from the user's ears.
The foregoing is merely illustrative of the principles of this
invention and various modifications can be made by those skilled in
the art without departing from the scope and spirit of the
invention. The foregoing embodiments may be implemented
individually or in any combination.
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